1. Field of the Invention
The present invention relates to an electronic device using electron transport proteins, and more specifically, it relates to an electronic device having rectifying characteristics or at least one of transistor and switching characteristics, which device is implemented in hyperfine size in biomolecular level by using electron transport proteins different in redox potential from each other as material therefor.
2. Description of the Prior Art
FIG. 1 is a sectional view showing a diode element in metal-oxide-semiconductor (MOS) structure employed in a conventional integrated circuit. Referring to FIG. 1, an n-type region 2 is formed on a p-type silicon substrate 1, and a p-type region 3 is partially formed in the n-type region 2. Further, an n-type region 4 is partially formed in the p-type region 3, followed by formation of SiO.sub.2 films 5 on the respective said regions. An electrode 7 is provided in contact with the p-type region 3, while an electrode 6 is provided in contact with the n-type region 4. As shown in FIG. 1, p-n junction is formed between the electrodes 6 and 7 by the junction of the p-type region 3 and the n-type region 4, thereby to attain diode characteristics.
FIG. 2 is a sectional view of a field-effect transistor (FET) employed in a conventional integrated circuit. Referring to FIG. 2, two p.sup.+ -type layers 103 are formed in an n-type silicon substrate 101 while a channel region 102 is formed between the p.sup.+ -type layers 103. SiO.sub.2 films 104 are formed on the surface of the substrate 101 while provided are a source electrode 105 in contact with one p.sup.+ -type layer 103, a gate electrode 106 on the channel region 102 through the SiO.sub.2 film 104 and a drain electrode 107 in contact with the other p.sup.+ -type layer 103 respectively. Transistor or switching operation of the conventional FET as shown in FIG. 2 is controlled by gate voltage which is applied to the gate electrode 106. Namely, current carriers in the surface layer between the source and drain electrodes 105 and 107 are changed in number in response to the gate voltage, thereby to control the current.
The conventional diode and transistor elements in the aforementioned structure can be hyperfinely processed, whereby LSIs of 256 Kbits employing the respective elements of the aforementioned structure are now put into practice. In order to improve such elements in storage capacity and arithmetic speed, the elements themselves must indispensably be in hyperfine structure, whereas mean free paths of electrons are substantially equalized to scales of the elements in hyperfine patterns of about 0.2 .mu.m in elements using Si and hence the independency of the elements cannot be maintained. Thus, it is anticipated that maturing silicon technology may run into a blank wall in the near future, and hence required is a VLSI based on a new principle which can crack the 0.2 .mu.m barrier.
On the other hand, the idea of an electronic device using proteins has already been known in the art such that, for example, methods of forming fine metal patterns with respect to protein films are disclosed in an article by James H. McAlear and John M. Wehrung entitled "Bioconductors--Beyond VLSI", IEEE-Japan, App. Phys. Sept. 7-11, 1981 and U.S. Pat. No. 4,103,064 granted to James H. McAlear et al., entitled "Microdevice substrate and Method for Making Micropattern Devices", Jan. 25, 1978. Further, a method of forming monomolecular protein films and molecular logic elements are disclosed in an article by James H. McAlear and John M. Wehrung entitled "Towards Three-Dimensional Biomolecular Logic", IEEE Computer Society MEDCOMP82, Sept. 1982. However, not yet known is an idea of attaining rectifying and transistor characteristics using electron transport proteins.